Four-year study looks at addition of winter grazing to crop rotation

Making your land work harder for you is the aim of a four-year grazing study being conducted at the Sunbelt Expo site in Moultrie, Ga. Results from the third year of this four-year trial were presented recently at the Expo Field Day.

The study focuses on the costs and returns of integrating winter beef grazing with irrigated summer crop production of cotton and peanuts. Researchers hope to show that year-round land use will increase profits for farmers.

A 10-acre plot at the Expo site has been divided into four 2.5-acre plots, explains Gary Hill, University of Georgia professor of animal and dairy science. Cotton and peanuts are planted during the summer on an alternate-year rotation.

Rye or ryegrass is planted in the winter for cattle to graze. Two of the plots are planted with no-till methods while the other two plots are planted using conventional-tillage.

“The idea here is to have a four-year rotation — two years of cotton and two years of peanuts,” explains Hill. “We have 70 by 42-foot areas that are fenced out during the winter months with no grazing. Adjacent to those areas are same-size plots that are not fenced.

“Samples then are taken from the grazed and ungrazed areas for dry-matter production during the winter. We're also looking at the yields of cotton and peanuts to determine the effect of grazing on those crops.”

In 2001, with cotton planted in the plot, grazing had no effect on final yields, says Hill. In both the grazed and ungrazed plots, cotton yielded about 1,100 pounds per acre. The tillage phase of the study favored minimum-tillage, with about 100 pounds more per acre of cotton, he adds.

This past year, with peanuts planted in the same area, grazing again had no effect on final yields, and the minimum-tillage peanuts yielded 400 pounds more per acre. The minimum-tillage plots, adds Hill, contained an ample amount of residue.

Grazing factors that may affect the crops include compaction of soil by the cattle and their natural fertilization, as well as residue from the rye.

“Prices for cattle have been pretty good for the past two to three years, and they're working better into this rotation situation,” says Hill.

The University of Florida, he says, is working on a multi-state study where bahiagrass is rotated to help break up nematode populations and to increase cotton and peanut yields.

“In this study, we're looking at adding value to the farming system by grazing cattle after cotton or peanuts. We used steers in the first year and heifers in the second and third years.

“We blocked off a 10-acre area here, stocking at one 500-pound animal per acre. This is a minimum stocking rate for the purposes of this study. On your farm - with good management - you could go with one and a half to two animals per acre.”

The animals in the study gained from 1.8 to 2 pounds daily, for 84 days in the first two years and only 57 days this past year, says Hill. “This added about $100 to $144 per acre during the 90-day period from January through March, just from the cattle grazing. Establishment costs run about $100 to $125 per acre, and that doesn't include the cost of fencing. However, fencing has become less expensive in recent years.”

Farmers in Georgia might have the option of a contract grazing system, says Hill. “With these systems, you're not required to own the cattle. You can contract with someone who will pay you for the gain from the cattle. They'll probably want you to take a truckload lot, and you need to read the fine print in any such contract.”

Thus far, the Expo study has shown that cattle can add value to farming systems, he says. “Take a hard look at cattle for this upcoming year. By increasing your stocking rate, you can spread costs over more animals, and you'll get more gain and more return per acres of land.”

Another feature of this year's Sunbelt Expo Field Day was an on-site demonstration of the basics of installing and reading a water meter on a center-pivot irrigation system. Water meters surfaced as a strong topic with Georgia lawmakers this year, making their eventual voluntary or required us on farms a certainty.

An agricultural water meter is a simple yet effective management tool for farmers, says David Bennett, deputy executive director of the Georgia Soil and Water Conservation Commission.

“The actual mechanism is similar to an internal wind vane in the line of the irrigation system, with a meter on the exterior,” says Bennett. Despite its lack of complexity, the metering system does account for factors such as pipe diameter and the water source to insure the measuring accuracy not found on pivot pressure gauges.

Normal irrigation systems are set up for gallons per minute, but farmers don't always use the full potential of the system, such as 500 to 600 gallons instead of 1,000 gallons per minute. Or, farmers may go over or under the set rpm's.

Bennett says the typical agricultural meter displays accurate readings of how much water is applied to a crop in inches per acre — which most farmers use — and feet per acre. It also shows the total gallons used each time a farmer irrigates his crops.

“These figures, along with measurements of rainfall, then may be used to manage more effectively — with the right amount of water for the crop and correct calibration for the pivots,” says Bennett.

End-of-the year totals tell the amount of water distributed by every pivot and how much water was used on each crop during the growing season. This information is helpful in finding the appropriate water needs for maximum crop yields and determining whether irrigation systems need to be repaired or upgraded.

The information produced by the water meter also includes helpful inputs for those with irrigation software programs and for farming neighbors. “Farmers in the same area can compare and share objective information on adjoining or nearby fields to further assist with management decisions,” says Bennett.